Bicycle Mechanics - Isn't this a little soon to be replacing the chain & cassette?

I've got almost 700 miles on the MTB and I'm already replacing the chain and cassette -- kinda soon, isn't it? Then again, maybe not: I'm a Clydesdale (205 - 210) and I like to grind pretty hard on the pedals, so maybe I'll just have to resign myself to buying drivetrain parts on a regular basis. I thought I was doing a sorta-decent job of keeping the chain & gears clean and lubed so they shouldn't have been ground down much by gunk and grit. The original chain and cassette were KMC Z-72 & SRAM 5.0 (11-32) -- do these parts suck enough to explain the short life?

The reason I'm replacing parts is that I checked the original chain and noticed a bit of stretch - a little less than 1/16" over 12" - and figured that I'd get a new chain and hope that all else would be okay. I never had any problems with the original setup... just thought I'd do a little preventive maintenance and head off any future problems. Got the new chain on and took it for a ride and noticed that when I got on the pedals a little bit in the middle gears the new chain was skipping. I checked my favorite gears on the cassette and noticed that they were more worn than I thought. I'm heading to the LBS tomorrow to get a new cassette... hopefully the new parts will last a little longer. :(

Let's just say there is better out there. Get an LX or higher cassette with a sram chain. That should last you longer.

SRAM cassettes and chain combos have a good rep for lasting a while. I use a SRAM 7.0 cassette with a SRAM chain. Its worked very well and has lasted a while. Also, like you said you have been doing, keeping the whole system clean will greatly prolong life. Good luck.

-Moab

Trying to convert...ummm...too tired. Ok here is my wear time on parts

1 - 2 months on chain (around 400km of hard single track)
2 - Freehub (once a month easily)
3 - Cassette (If I change the chain often enough every 3-6 months)

If you are noticing a skip you may want to check the freehub. It could be you are getting such a large wobble that your freehub is shot and needs replacing.

I am also a clydesdale rider (heavier than yourself) and torque hard on my bike. Definately keep tabs on your freewheel, you can generally ride your cassette into crap but a bad freewheel makes the ride much worse.

It depends on the conditions that you ride in. I have about 3500 miles on my road bike chain-it's always cleaned with citrus cleaner and lubed with kry-tech wax lube, and rarely driven in wet or dirty conditions. OTOH, I got only about 500 miles out of a chain that I rode through that awful winter 2 years ago-salt, slush, snow and sand every day for 4 months. It also killed the cogs, but they had some mileage on them.

Anybody have an opinion on Shimano chains, especially the CN-HG70 that the LBS set me up with? I haven't had a chance to ride it yet since I just got the new cassette today and it's been pouring rain all day, but I can't seem to find much info on it online. The closest I can find is reviews on the CN-HG72 on mtbr and just about everybody complains about it breaking. I know better than to believe everything I read there, but when everybody has the same complaint there might be something to it. I know about the special pin and I used it when I put the chain together. How different is the CN-HG70 from the CN-HG72? Also, is there any problem running a 9-spd chain on an 8-spd cassette? Maybe I'm worrying for nothing but the info I've seen so far on Shimano chains makes me nervous about riding this one... :(

I think 1 is 9 speed and the other is 8 speed. Both are the standard chains on shimano drive train systems. They are ok.

Originally posted by Maelstrom
Trying to convert...ummm...too tired. Ok here is my wear time on parts

1 - 2 months on chain (around 400km of hard single track)
2 - Freehub (once a month easily)
3 - Cassette (If I change the chain often enough every 3-6 months)


That sounds like overkill to me. I know a chain is good for 3,000 miles or so. Maybe less on the mountain bike but it also takes alot longer to put miles on compared to the road bike.
Freehub? I never change the freehub and I have sealed bearings so I don't really do anything to it...
cassette doesn't get changed unless I change the chain a few times or if I notice it start to skip or sloppy shifting.

I don't know, maybe the clydsdale weight has a larger factor than I thought but maybe you have alot of good, used stuff laying around!

I do lube the chain often and keep it clean so maybe that is a secret to long drivetrain life.

Originally posted by RacerX
That sounds like overkill to me. I know a chain is good for 3,000 miles or so. Maybe less on the mountain bike but it also takes alot longer to put miles on compared to the road bike.

Well, for what it's worth I asked the guy at the shop about the expected lifetime of MTB chains and cassettes and he said that 500-700 miles is about right if you ride it hard. I didn't ask him about road bikes but it seems reasonable that you'd get longer life based on not riding through a lot of gunk and grit and maybe less hard grinding on the pedals than would be the case on a MTB. Beats me... I'm just learning this stuff! :D

Yeah, I guess it varies depending on the terrain you ride. I do know the more often you change your chain, the longer everything else lasts but there is the law of diminishing returns on that.

800-1000 miles doesn't sound unreasonable to me for a mtb chain...

Originally posted by RacerX


That sounds like overkill to me. I know a chain is good for 3,000 miles or so. Maybe less on the mountain bike but it also takes alot longer to put miles on compared to the road bike.
Freehub? I never change the freehub and I have sealed bearings so I don't really do anything to it...
cassette doesn't get changed unless I change the chain a few times or if I notice it start to skip or sloppy shifting.

I don't know, maybe the clydsdale weight has a larger factor than I thought but maybe you have alot of good, used stuff laying around!

I do lube the chain often and keep it clean so maybe that is a secret to long drivetrain life.

Well I also leg press in the 1000pnd range and torque harder than anyone I currently know and ride with. I find freehubs very very easy to destroy in the Shimano level drive train. I can and have snapped my Shimano chain on a steep climb if I try to leave it in a harder gear. This happens after a break in period of course. I have yet to break a new chain just by pedaling hard ;)

I clean and lube my bike after almost every ride and take very very good care of the drive train. I do this because of the very muddy nature of BC. I just think the difference between mtb and road is very very different especially if you start throwing in trials stuff (such as lurches, pedal kicks and wheelie drops where you SLAM the pedals 1/4 turn to pop you up).

Being a clydesdale helps but everyone I ride with goes through parts in around the same amount of time unless you have higher end freehubs. Would you believe in 6 months I have also almost completely rounded the sprockets on my deraileur? I go through drive train parts very quickly and always have especially now that I ride in Whistler. :)

Isn't 800miles 400km approx? or do I have the conversion backwards (yes I am being to lazy to look it up right now)

And nothing lying around. Unless I know it can be fixed I toss everything. :)

I usually put 1500-2000km on a cassette for my road bike depending on the terrain i ride on.